Alignment gauge for casting patterns



p 1969 s. M- HANSON 3,465,451

ALIGNMENT GAUGE FOR CASTING PATTERNS Filed March 21, 1967 INvzN'roR SHERWOOD MHANSQN United States Patent 3,465,451 ALIGNMENT GAUGE FOR CASTING PATTERNS Sherwood M. Hanson, S. Main St., Sandwich, Ill. 60548 Filed Mar. 21, 1967, Ser. No. 624,848 Int. Cl. G01b /14 U.S. Cl. 33-180 3 Claims ABSTRACT OF THE DISCLOSURE An alignment gauge for detecting relative shift of casting patterns on a pattern board is characterized by adjustable probe arms to accommodate different thicknesses of pattern boards, and an adjustable sliding stop which allows the gauge to be inserted a predetermined distance from the edge of the pattern board.

This invention relates generally to foundry equipment, and in particular to a device for detecting the relative shift of casting patterns after they have been assembled on opposite sides of a pattern board in preparation for making a sand mold.

For many years, foundries have practiced the technique of using split molds for casting articles of complex shape. These molds, generally made of sand, are commonly split into halves along a parting line which comprises the plane at which the two halves of the mold meet. The molds themselves are commonly made from wooden patterns which are split along a corresponding plane to allow the mold to be made in two halves, whereupon the mold halves may be placed together for pouring. Alignment of the mold halves is insured by the technique of placing the two pattern halves on opposite sides of a single mold plate or board, and making the mold halves simultaneously in a fixture provided for this purpose. When the halves are separated, the mold plate with its attached pattern half is removed, and the two halves of the mold are then placed together to form the completed mold.

In preparing the mold plate prior to making the mold, it is essential that the pattern halves be accurately aligned on opposite sides of the plate. If they are at all shifted from perfect registry, the resulting mold halves will be shifted an equal amount, causing the resulting casting to be skewed at the parting line of the mold. With small castings in particular, such a shift is often intolerable and results in many rejected castings in practice. Similar problems arise in the positioning of core prints and gating on the mold board when complicated castings are involved.

In the past, attempts have been made to solve the problem of lack of registry of pattern halves on the mold board by securing the patterns with dowels which pass through closely-fitting holes in the mold board. However, if these holes are not accurately sized, or if they are drilled at an angle, the patterns may still be shifted out of registry. While this technique is useful, it has not solved the problem. The only practical method of insuring perfect registry of patterns on the mold board is to check them for registry prior to making the mold. In this Way, errors can be detected and changes made before a number of expensive molds have been made and castings poured.

One such checker that has been used in the past is a tuning-fork shaped device which slips snugly over the mold board and has accurately aligned faces at the tips which are used to check the pattern alignment. If shift has occurred, the tips will not contact the pattern halves simultaneously on opposite sides of the board, and there will be a gap on one tip or the other. This can easily be detected by the foundryman and the pattern shift corrected. However, gauges of this kind have generally been made out of non-durable materials such as wood, and tend to become distorted and damaged in use. Another problem is that a given gauge can be used only with a given mold board, and with mold boards of different thicknesses different gauges must be used. Where portions of the pattern are to be placed a predetermined distance from the edge of the mold board, special gauges must also be constructed, often for only a single job, after which they are no longer needed. The use of such gauges is an uneconomical expense for a foundry, especially foundries which specialize in job items and limited production castings.

Accordingly, a principal object of the present invention is to provide a durable, accurate alignment gauge for checking the shift of casting patterns on a mold board. It is further intended that the gauge be adjustable to accommodate mold boards of the varying thicknesses, with such adjustment being easily performed by the foundryman from one job to the next without the loss of accuracy or alignment. A further object of the invention is to provide an adjustable stop on the gauge which may be preset to stop the gauge at a predetermined distance from the edge of the mold board for the purpose of checking gates, risers, and the like. It is also intended that the gauge be durable and maintain its accuracy throughout a long period of use.

Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings, in which:

FIG. 1 is a plan view of the alignment gauge of the present invention, shown as its would be used in connection with a pattern mounting board (shown in phantom);

FIG. 2 is a side elevation of the gauge of FIG. 1;

FIG. 3 is a section taken in the plane 33 of FIG. 1;

FIG. 4 is an enlarged section of a portion of the gauge tip, taken in the plane 44 of FIG. 3; and

FIG. 5 is an enlarged section of the gauge illustrating the adjustable stop, taken in the plane 55 of FIG. 3.

While the invention will be described in connection with a preferred embodiment, it will be understood that I do not intend to limit the invention to that embodiment,

.but intend to cover all alternative and equivalent constructions as may be included within the spirit and scope of the invention.

Turning first to FIG. 1, an alignment gauge constructed according to the present invention is shown as it would appear in use. The gauge consists of an upper probe arm 10 and a lower probe arm 11 which are maintained in alignment by a pair of guide members, which in this embodiment comprise rods 12. The guide rods are carried by the upper probe arm 10 and secured by pins 13 which rigidly hold them in place. Corresponding bores 15 in the lower probe arm 11 receive the guide rods 12 and rigidly locate the probe arms 10, 11 in alignment with each other.

At the ends of the probe arms 10, 11 the alignment faces are located. Each arm is formed at its top with a contact portion 16 having an accurately machined bottom surface 17 and edge surfaces 20, 21, 22 which are brought into abutting relationship with the pattern halves for checking pattern alignment against the mold plate.

In accordance with one aspect of the invention, the bottom surfaces 17 at the contact portions 16 of the probe arms 10, 11 are maintained in parallel alignment opposite to one another by the guide rods 12 which are slidably received in corresponding bores 15 as previously described. The guide rods 12 are made of sufficient length to substantially engage the full length of the bores 15 during the entire range of useful separation of the probe arms 10, 11 so as to maintain accurate alignment with mold boards of varying thickness.

Further in accordance with the invention, the separation of the contact portions 16 of the probe arms 10, 11 is selectively adjustable by means of an adjustment knob 25. This is achieved by providing a threaded shaft 26 which is secured at its upper end to the adjustment knob 25 and rotatably received within a bore 27 in the upper probe arm 10. The opposite end of the shaft 26 is received within a corresponding threaded receptacle 28 in the lower probe arm 11. A compression spring 30 is provided to urge the upper probe arm away from the lower probe arm 11 and into restraining engagement with the adjustment knob 25, which serves as a stop. The compression spring is located in counter-sunk bores to locate the ends of the spring and to provide for additional spring length to prevent the spring coils from stacking up solidly when the probe arms 10, 11 are brought into close proximity to each other, as when checking patterns on very thin mold plates, or when checking or correcting the alignment of the gauge itself as will be hereinafter described.

It will be observed that the contact portions 16 of the probe arms 10, 11 are provided with edge surfaces 20, 21, 22 which are maintained in absolute parallelism throughout the range of adjustment provided by the adjustment knob 25. To achieve this end, the final machining of the contact portions 16 of the arms 10, 11 is left until the end of the machining operations, after the gauge has been assembled. Prior to final machining, the arms 10, 11 are brought together so that the contact portions 16 are pressed rigidly together. The two contact portions 16 may then be machined as a single unit, assuring perfect alignment. Alignemnt may be checked at any later time merely by again bringing the arms 10, 11 together until the contact portions 16 meet. If the edges 20, 21, 22 should be out of alignment, this will be immediately evident.

As an additional feature of the invention, an adjustable stop is provided so that the gauge may be easily introduced a fixed predetermined distance from the edge of the mold plate in order to check the position of patterns, cores, risers, and the like. This is accomplished by provisions of a rail 31 on one of the probe arms 10, 11, in this case the upper probe arm 10. The rail is located longitudinally relative to the upper probe arm 10, and is seated at one end in a bore 32 and secured at the other in a similar bore 33 by a set screw 35 or other fastening means. As is best illustrated in FIG. 3, the rail 31 is held in parallel alignment to the planes of the contact portions 16 of the probe arms 10, 11. Carried by the rail 31 is an adjustable stop 36 which, in the preferred embodiment, is a T-shaped member having a bore which receives the rail 31 and a widened portion 38 with an abutting surface 40 which engages the edge of the mold board to locate and position the guage with respect to the mold board. A set screw 41 having a knurled knob 42 is provided to selectively secure the stop 36 in any desired position along the rail 31.

For use, the foundryman merely adjusts the width of the gap between the contact portions 16 by turning the adjustment knob 25. When the gap is such as to allow the gauge to slip smoothly over the mold board, the adjustable stop 36 is set, if desired, by means of the set screw 41 to limit the entrance of the gauge to a predetermined value. The foundryman then has only to slide the gauge over the mold board, bringing the contact portion 16 into contact with various portions of the pattern halves to check that both upper and lower probe arms 10, 11 touch the corresponding portions of the pattern halves. Should a gap exist, this indicates that the patterns have shifted out of alignment and must be reset.

In the preferred embodiment, the upper and lower arms 10, 11 of the gauge are made of cast metal, such as aluminum. The guide rods 12 are preferably constructed of a harder material, such as steel rod, to withstand wear and provide rigid location for the arms 10, 11. The use of aluminum for the arms 10, 11 provides an additional advantage in that the contact surfaces 20, 21, 22 of the contact portions 16 may be easily re-machined into alignment should they become bent or damaged during use.

I claim as my invention:

1. A gauge for detecting the shift of mounted casting patterns comprising, in combination, first and second oppositely disposed elongate probe arms having a plane of separation defining a gap adapted to receive the edge of a pattern board, for locating said arms in parallel alignment over a range of separation between being pressed rigidly together and a maximum opening position, each of said probe arms having a terminal contact portion, said contact portions having common coplaner contact surfaces perpendicular to said plane of separation for contacting the corresponding halves of separated patterns mounted on a pattern board, and means for adjustably spacing said arms along said range of separation, said means including a. rotatable shaft having a knob and a threaded portion and a compression spring surrounding said shaft, and in which said arms include oppositely disposed bores perpendicular to the plane of separation for receiving said shaft, one of said bores being threaded to receive and position one end of said shaft, said bores in addition being counter-sunk inwardly from the plane of separation by a combined distance at least equal to the compressed length of said spring to allow the arms and contact portions to be pressed rigidly together at the inner limit of the range of arm separation.

2. A guage as defined in claim 1 in which one of said probe arms carries a longitudinal rail parallel to said arm, and having a slidable member carried by said rail having an edge surface perpendicular to said plane of separation, said edge surface protruding into said gap for abutting the edge of said pattern board, and securing means for selectively securing said slidable member at a predetermined position relative to said rail, whereby said slidable member stops the introduction of said gauge at a predetermined distance from the edge of said pattern board.

3. A gauge as defined in claim 1 in which said guide means comprises first and second parallel guide members carried by one of said arms, and first and second bore receptacles carried by the other of said arms for slidably receiving and guiding said guide members.

References Cited UNITED STATES PATENTS 3,293,764 12/1966 Born 33l80 2,956,343 10/1960 Shaff r 33174 2,591,314 4/1952 Stelmach 33-180 LEONARD FORMAN, Primary Examiner ROGER A. FIELDS, Assistant Examiner 

